The day after I purchased my 2017 CB1100EX, I began looking for a rear luggage rack and a top case. I assumed a few well-written Google queries and patience would result in a new OEM Top case I could purchase, Surely something was left in inventory somewhere in the United States, Europe, or Japan. Surprisingly, that was not the case, pun intended.
It appears that some mischievous engineer at Honda enjoyed tweaking rear luggage racks every month, making backward compatibility impossible. And from what I can tell, the 2017 CB1100EX had very few accessories manufactured because that model was a limited run. Honda clearly likes to turn its inventory relatively quickly, and they are simply not interested in keeping something in the warehouse in anticipation that I may buy something someday.
As I looked at your posts and saw those beautiful top cases, I grew more resolute. 22 months into my search, I was able to purchase a used rear rack from Germany. Someone parted out a CB1100EX, and for once in my life, I actually paid a reasonable amount of money for a hard-to-source accessory.

I documented that experience in this Thread:
https://cb1100forum.net/forum/showthread.php?tid=14378
I gave up on the Honda OEM Top Case. After two failed transactions with resellers that did not understand what they actually held in inventory, I decide to turn to one of my favorite suppliers: SW-Motech. I purchased an Urban ABS Top Case:
https://sw-motech.us/en-us/p/40525720551....22000%2FB
Curb appeal is very important to everyone on this Forum. I believe this after-market case works well with the CB1100 aesthetic. Here are a few pictures for your review:
The Top Case has a great internal lining with a rubber insert that protects items you place inside it. In its standard configuration, it can hold 16L. When expanded, it can hold 29L.
I welcome your feedback. If this posts sparks any interest, I will create another thread documenting the installation. Enjoy your week. David